A metal oxide thin film transistor uses a metal oxide semiconductor layer as an active layer of the thin film transistor. Because of its optical properties such as a high carrier mobility, a low deposition temperature, and a high transparency, the metal oxide thin film transistor has become a prevailing display panel driving technology.
The display panels have relatively high requirements on the positive bias stability of the metal oxide thin film transistor disposed in the display region, and when the stability of the metal oxide thin film transistor in the display region is poor, display images may easily show issues such as residual images or uneven brightness of the display device. Accordingly, the positive bias stability of the metal oxide thin film transistor in the display region needs to be improved to enhance the display quality of the display panel.
Further, when the metal oxide thin film transistor disposed in the non-display region of the display panel is an N-type thin film transistor, often a threshold voltage higher than or equal to a certain threshold voltage value (e.g., 3V) is needed to ensure that the thin film transistor is in an “off” state when the voltage between the gate and source electrodes of the metal oxide thin film transistor is zero.
However, according to the present disclosure, it is found that the greater the threshold voltage of the metal oxide thin film transistor, the poorer the positive bias stability. Accordingly, the metal oxide thin film transistor may not simultaneously satisfy the requirements of the display panel regarding the positive bias stability and the threshold voltage.
The disclosed array substrate and fabrication method thereof, and display panel are directed to solving at least partial problems set forth above and other problems.